Kirra has two engines for combining surfaces and solids. They are complementary — when one struggles with a pair, the other often succeeds.
| Solid Boolean | Trimesh Boolean | |
|---|---|---|
| Works on | Closed, watertight solids | Open surfaces and solids |
| Size | Small to medium — asks first over 60,000 triangles | Large meshes |
| Runs | In the foreground | In the background, with progress |
| You choose | One operation | The pieces to keep, or a quick operation |
| Fix the result | Repair options | Reclassify, close and cleanup options |
| Result layer | Booleans | Booleans |
Use Solid Boolean for two clean solids — extruded design volumes, a bench solid against a pit shell.
Use Trimesh Boolean for anything open — a design against topography, a pit shell against a pickup — and for large or messy meshes.
Mesh booleans are a very difficult space to work in. Make your meshes as clean and watertight as you can — Clean Mesh first — and if one engine fails, try the other on the same pair.
Kirra’s earlier Surface Boolean tool has been retired. Notes or screenshots that mention it no longer apply.
For booleans on KAD polygons rather than surfaces, see KAD Boolean.